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A Modified SLM Scheme With Low Complexity for PAPR Reduction of OFDM Systems
Seok-Joong Heo,Hyung-Suk Noh,Jong-Seon No,Dong-Joon Shin IEEE 2007 IEEE transactions on broadcasting Vol.53 No.4
<P>In this paper, we propose a new peak-to-average power ratio (PAPR) reduction scheme of orthogonal frequency division multiplexing (OFDM) system, called a modified selected mapping (SLM) scheme, which considerably reduces the computational complexity with keeping the similar PAPR reduction performance compared with the conventional SLM scheme. The proposed scheme is analytically and numerically evaluated for the OFDM system specified in the IEEE 802.16 standard. For the OFDM system with 2048 subcarriers, the proposed scheme with 4 binary phase sequences can reduce the complex multiplications by 63.5% with the similar PAPR reduction compared with the SLM scheme with 16 binary phase sequences.</P>
직교 주파수 분할 다중화 시스템에서 최대전력 대 평균전력의 비를 줄이기 위한 연산량이 적은 새로운 선택사상 기법
허석중(Seok-Joong Heo),노형석(Hyung-Suk Noh),노종선(Jong-Seon No),신동준(Dong-Joon Shin) 한국통신학회 2007 韓國通信學會論文誌 Vol.32 No.11C
본 논문에서는 직교 분할 주파수 다중화 (이하 OFDM) 시스템에서 최대전력 대 평균전력의 비 (이하 PAPR)를 줄일 수 있는 새로운 선택사상기법 (selected mapping; 이하 SLM) 방법에 대해서 제안한다. 제안된 방법의 PAPR 감소 성능은 기존의 SLM과 동일하게 유지하면서도 연산 복잡도는 크게 감소시킨다. 또한, 본 논문에서는 모의실험을 통하여 IEEE 802.16에 제안된 표준에 근거한 OFDM 시스템을 수식적이고 해석적으로 분석하였다. 2048개의 부반송파를 사용하는 시스템에서 본 논문에서 제안하는 방법을 이용하여 4개의 서로 다른 위상 시퀀스를 생성하여 (U=4) PAPR 감소에 이용하는 경우 기존의 SLM에서 16개의 서로 다른 위상 시퀀스를 이용하여 (U=16) PAPR을 줄이는 경우와 비슷한 PAPR 감소 성능을 가지면서도 연산복잡도는 63.5% 감소되었다. In this paper, we propose a new peak-to-average power ratio (PAPR) reduction scheme of orthogonal frequency division multiplexing (OFDM) system, called a modified selected mapping (SLM) scheme, which considerably reduces the computational complexity with keeping the similar PAPR reduction performance compared with the conventional SLM scheme. The proposed scheme is analytically and numerically evaluated for the OFDM system specified in the IEEE 802.16 standard. For the OFDM system with 2048 subcarriers, the proposed scheme with 4 binary phase sequences can reduce the complex multiplications by 63.5% with the similar PAPR reduction compared with the SLM scheme with 16 binary phase sequences.
Bariatric surgery versus conventional therapy in obese Korea patients
Yoon-Seok Heo,Joong-Min Park,Yong-Jin Kim,Seong-Min Kim,Do-Joong Park,Sang-Kuon Lee,Sang-Moon Han,Kyung-Won Shim,Yeon-Ji Lee,Ja-Youn Lee,Jin-Won Kwon 대한외과학회 2012 Annals of Surgical Treatment and Research(ASRT) Vol.83 No.6
Purpose: In Korea, the results of bariatric surgery have not been compared with those of nonsurgical treatment. The purpose of this study was to evaluate the effectiveness and safety of bariatric surgery vs. conventional nonsurgical treatment in severely obese Koreans. Methods: In this retrospective cohort study, we reviewed the medical charts of 261 consecutive subjects who underwent bariatric surgery and 224 subjects who were treated with weight control medication and lifestyle modification therapy between January 2008 and February 2011. Measures of clinical effectiveness, including change in weight (%) and comorbid diseases, and occurrence of complications, were investigated for 18 months after bariatric surgery. Results: Body mass index (BMI) was higher in the surgery group than in the conventionally treated group (mean ± standard deviation, 39.0 ± 6.2 vs. 34.3 ± 3.8). Diabetes was more prevalent in the surgery group than in the conventionally treated group (39.1% vs. 12.9%). The change in weight (%) between baseline and 18 months posttreatment was significantly greater in the surgery group (22.6%) than in the conventional therapy group (6.7%). While 57%, 47%, and 84% of subjects recovered from diabetes, hypertension, and dyslipidemia, respectively, in the surgery group, 10%, 20%, and 24% of subjects recovered from these conditions in the conventional group. Fifty-one subjects (19.5%) in the surgery group reported 61 complications (23.4%). Conclusion: Bariatric surgery in Korea was significantly more effective than conventional treatment for weight loss and recovery from comorbidities such as diabetes, hypertension, and dyslipidemia, with a reasonable complication rate.
Heo, Jin Hyuck,Im, Sang Hyuk,Kim, Hi-jung,Boix, Pablo P.,Lee, Suk Joong,Seok, Sang Il,Mora-Seró,, Ivá,n,Bisquert, Juan American Chemical Society 2012 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.116 No.39
<P>The Sb<SUB>2</SUB>S<SUB>3</SUB>-sensitized photoelectrochemical cells (Sb<SUB>2</SUB>S<SUB>3</SUB>–SPECs) in cobalt electrolyte were fabricated by depositing Sb<SUB>2</SUB>S<SUB>3</SUB> on the macroporous TiO<SUB>2</SUB> nanorods electrodes and consecutively spin-coating P3HT (Poly-3-hexylthiophene) interlayer to relieve the mass transport problem at vicinity of Sb<SUB>2</SUB>S<SUB>3</SUB> and cobalt redox couples and reduce the backward recombination. Through the introduction of P3HT interlayer, we could greatly enhance the power conversion efficiency of Sb<SUB>2</SUB>S<SUB>3</SUB>–SPEC to 4.2% at 1 sun illumination, whereas the Sb<SUB>2</SUB>S<SUB>3</SUB>–SPEC without P3HT interlayer exhibits 3.2% of device efficiency. The electrochemical impedance analysis let us know that the improved device performance was mainly attributed to the reduced backward recombination building up the higher open circuit voltage.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2012/jpccck.2012.116.issue-39/jp305150s/production/images/medium/jp-2012-05150s_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp305150s'>ACS Electronic Supporting Info</A></P>
An Overview of Peak-to-Average Power Ratio Reduction Schemes for OFDM Signals
임대운,Seok-Joong Heo,노종선 한국통신학회 2009 Journal of communications and networks Vol.11 No.3
Orthogonal frequency division multiplexing (OFDM) has been adopted as a standard for various high data rate wireless communication systems due to the spectral bandwidth efficiency, robustness to frequency selective fading channels, etc. However, implementation of the OFDM system entails several difficulties. One of the major drawbacks is the high peak-to-average power ratio (PAPR), which results in intercarrier interference, high out-of-band radiation, and bit error rate performance degradation, mainly due to the nonlinearity of the high power amplifier. This paper reviews the conventional PAPR reduction schemes and their modifications for achieving the low computational complexity required for practical implementation in wireless communication systems.
진중현(Joong Hyun Jin),권한올(Han Ol Kwon),하예진(Yejin Ha),허석현(Seok Hyun Heo),이정민(Jeongmin Lee) 한국식품영양과학회 2017 한국식품영양과학회지 Vol.46 No.9
본 연구에서는 잣피 열수, 20% 주정, 50% 주정 추출물들이 항염증과 항산화에 미치는 영향을 확인하기 위하여 ABTS 항산화능과 SOD, CAT, GPx 항산화 효소, NO의 분비량, 염증성 cytokine의 분비량을 살펴보고자 하였다. 잣피 열수, 20% 주정, 50% 주정 추출물 중 20% 주정 추출물이 항산화능, 항산화 효소 활성 증가, NO의 분비량 감소, 염증성 cytokine 분비량을 감소시켜 염증반응과 항산화 반응에 도움을 주어 내부에서 생성된 활성산소종과 외부로부터 침입한 미생물, 감염된 세포나 종양세포 등을 효과적으로 제거할 수 있을 것이라 예상할 수 있었다. 이는 염증뿐만 아니라 면역반응에서도 영향을 미칠 것이라 생각되며 염증조절 및 항산화 반응에 긍정적인 변화를 보였으므로 추후 염증 조절제로서 기능성 식품의 상업화에 기초 자료가 되어 국내 기능성 소재로서의 개발 가능성을 기대할 수 있다. The present study examined the anti-inflammatory and anti-oxidative effects of Pinus koraiensis (PK) cone shell extracts in vitro. Anti-inflammatory and anti-oxidative effects of PK cone shell extracted with hot water, 20% ethanol (EtOH), or 50% EtOH were examined using 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activites, as well as nitric oxide (NO) and anti-inflammatory cytokine measurements. The 20% EtOH extract of the PK cone shell decreased the NO and inflammatory cytokines secretion, and increased the ABTS radical scavenging, SOD, CAT, and GPx activities. This indicates that the 20% EtOH extract of the PK cone shell would be helpful in inflammation and oxidation systems. Therefore, the 20% EtOH extract of PK cone shell has great potential as a useful health food.